1889.] Effect of Floor-deafening in Dwelling Houses. 351 



largely increases, and the mean age at death diminishes. The results 

 of the present paper show that the sanitary condition of the floor- 

 deafening follows a similar order, thus : - 



The results obtained by the authors referred to above have also shown 

 that the micro-organisms do not come either from the breath (at least 

 in health), nor in large numbers from the outside air, so that it would 

 seem clear that they come from some part of, or material in, the room 

 itself. Though our results are certainly not so marked as those of 

 Dr. Emmerich, they show, nevertheless, quite clearly that the 

 deafening material may be and is in the poorer class of houses a 

 source of contamination of the air of dwellings, in that it furnishes a 

 good and suitable medium for the growth of micro-organisms, and 

 gives off foatid gases from putrefaction, provided the necessary factors, 

 moisture, warmth, and nitrogenous organic matter, are present. 



* Had it not been for the abnormally high results obtained in one of these 

 houses in which the drainage was very defective, these numbers would have been 

 very much lower, viz., 0'004 per cent. Cl and 0'0057 nitrogen. Indeed, eight of 

 the eleven houses examined were quite free from both chlorides and nitrogenous 

 organic matter. 



